The invention relates to a method of, and an apparatus for, raising sheet-like products, in particular printed products, which are taking part in a conveying process and follow sequentially one after the other, the products resting, at least in certain regions, on a conveying means during the conveying process.
In certain application cases, it is necessary for products transported, for example, on a conveying belt to be turned through 180xc2x0 in relation to an axis parallel to the conveying direction. This is achieved according to the prior art, for example, by so-called xe2x80x9crotary beltsxe2x80x9d in which the products are retained between two belts which are twisted parallel to one another through 180xc2x0 along the conveying direction. In order to avoid damage to the products and to ensure reliable turning, these rotary belts have to extend over a relatively large region of the conveying belt, which is disadvantageous in respect of the amount of space taken up by the turning apparatus.
In other application cases, it is necessary for the conveying direction of products transported, for example, on a conveying belt to be changed abruptly by a predetermined angle, in particular by an angle of 90xc2x0. According to the prior art, this is achieved, for example, in that running at the end of the first conveying belt is a second conveying belt, which extends at right angles to the first conveying belt and of which the conveying plane is arranged beneath the conveying plane of the first conveying belt, with the result that the products can drop onto the second conveying belt and thus change their conveying direction by 90xc2x0. It is disadvantageous here, for example, that the products drop between the two conveying planes in an uncontrolled manner, which may result in disruption. It is further disadvantageous that for example, if when the conveying direction is changed, upstream or downstream, the products are also to be turned, this can only be achieved by means of separate turning apparatuses or rotary belts, which in turn is disadvantageous in respect of the amount of space taken up. The same applies if when the conveying direction is changed, upstream or downstream, the products are to be rotated about an axis running perpendicularly to the conveying plane or a combination of the abovementioned operations of changing the conveying direction, turning and/or rotating are to take place in any desired time sequence.
It is an object of the invention to develop a method of the type mentioned in the introduction such that products supplied sequentially by a conveying means can be processed further individually with reduced mechanical outlay, the intention also being, in particular, to achieve the situation where the conveying means is only overlapped to a slight extent, if at all, by the apparatus for raising the products.
This object is achieved according to the invention in that, during at least a period of time of the raising operation, gravitational force being overcome in the process, the products are pivoted actively about an axis which extends essentially parallel to the direction in which the conveying process is oriented immediately prior to the raising operation.
At the beginning of the raising operation, a redirection of the movement of the products thus takes place to the effect that the forward movement brought about by the conveying process is slowed down, and a laterally oriented pivoting movement commences during this slowing-down operation. For this pivoting movement, which is oriented laterally in relation to the direction of the conveying process, the product has to be fed potential energy at least for a period of time, with the result that it is possible for the products to be pivoted upward during the above-mentioned period of time. Once the abovementioned period of time has elapsed, the products thus have higher potential energy than prior to this period of time.
Since the pivoting of the products commences in each case when a product arrives at a defined position or at the end of the conveying means, all the products are pivoted individually one after the other, with the result that, with products following one after the other quickly or in imbricated formation, a fan-like structure is produced during the pivoting operation, each fan element of said structure being formed by precisely one product in each case, with the result that it is easily possible for the individually fanned-out products to be further processed individually. This is because, once the products have executed the pivoting movement according to the invention, they can easily be, for example, gripped and removed individually from their individually fanned-out structure or deposited individually on a further conveying means.
Instead of individual products being conveyed and pivoted, it is also possible for groups of products to be conveyed and/or pivoted in each case. The product groups here may be formed during the conveying operation preceding the pivoting operation, with the result that even the conveying operation takes place in groups. It is also possible, however, for the product groups only to be formed immediately prior to commencement of the pivoting operation or even during the pivoting operation, which means that, shortly prior to or during the pivoting operation, individual products following one after the other, for example, in imbricated formation are pushed essentially congruently one above the other to form groups.
The pivoting movement provided according to the invention further achieves the situation where the transfer between two conveying means which follow sequentially one after the other can take place with an extremely small amount of space being required since the two conveying means only need to overlap one another slightly, this overlapping being, for example, in the order of magnitude of the longitudinal extent of a product in the conveying direction.
It is advantageous if the pivot axis which is decisive for the pivoting movement according to the invention coincides at least essentially with a product edge which extends parallel to the direction in which the conveying process is oriented immediately prior to the raising operation. In this case, the products are pivoted about one of their edges, which, on the one hand, means that the pivoting movement can be executed with a minimal amount of space being required and, on the other hand, advantageously results in the products only having to be accelerated to an unproblematic extent. In this case, the edge about which the pivoting movement takes place is advantageously not accelerated at all in practice.
Immediately prior to the beginning of the raising operation, the products may be oriented horizontally or in a manner inclined in relation to the horizontal. It is advantageous here if the products rest with their surface area on a correspondingly oriented conveying means, in particular a conveying belt.
It is likewise possible, however, to convey the products by means of grippers, which then transfer the products, for the purpose of the pivoting operation according to the invention, to a corresponding pivoting apparatus. These grippers can retain the products, for example, at one or two edges.
Throughout the pivoting movement, the products are preferably pivoted through an angle of between 10xc2x0 and 270xc2x0, the raising-operation period of time, over which the gravitational force is overcome, usually always accounting for an angle range of between 10xc2x0 and 90xc2x0. It is thus possible according to the invention for the products first to be raised through an angle range of between 10xc2x0 and 90xc2x0 and then to be pivoted downward, for example assisted by gravitational force, through an angle range of between 90xc2x0 and 180xc2x0.
In order for it to be possible for the pivoting movement according to the invention to be executed in a defined manner, it is possible, during this pivoting movement, for the products to be retained at least temporarily, in particular at their leading edge, as seen in the conveying direction, by suitable means, e.g. by supporting means or grippers, which cause the products to pivot and pivot along with said products. In particular each product here is assigned an individual gripper, of which the movement, ultimately, determines the speed of the pivoting movement of the products. Immediately prior to the beginning of the pivoting movement, the products may be moved, by way of their leading edge, into the gripper by the conveying movement. It is likewise possible for a suitable apparatus to guide the grippers, counter to the conveying movement, up to the leading edge of the products in order then to grip the latter.
It is preferred if, at the beginning of the raising operation, the products are moved, by way of their leading edge, against an in particular stationary stop, with the result that the products, at least in certain regions, lift off from the conveying means in the pivoting direction. This stop thus initiates the pivoting movement according to the invention in that, for example in a region of the leading edge of the products which is directed away from the pivot axis, it prevents further movement in the conveying direction, which results in the products xe2x80x9cbulging outxe2x80x9d upward on account of the action of friction between the conveying means and products. This bulging out takes place in each case in a defined direction away from the conveying means, with the result that the abovementioned stop triggers a controlled and defined initiation of the pivoting movement, whereupon the rest of the pivoting movement in the upward direction can take place in a controlled manner by way of a gripper or a suitable supporting means.
It is particularly preferred if, at the beginning of the raising operation, products having an overfold are only moved against a stop of the abovementioned type by way of the leading edge of their overfold region, with the result that that region of the products which is located opposite the overfold lifts off from the overfold in the pivoting direction and the products are thus made to open. In this case, the stop thus results both in the pivoting movement being initiated and in the products being opened.
As an alternative, or in addition, to the abovedescribed stop, it is also possible to provide, in the region of the conveying means, an in particular stationary guide element, along which the products are moved by way of their leading edge at the beginning of the raising operation. The guide element causes, at least in certain regions, the products to be raised from the conveying means in the pivoting direction. If then a stop is also provided in addition, for example at the end of the guide element located in the conveying direction, products with an overfold can first of all be raised by the guide element, whereupon the raised products are then opened by way of the overfold butting against the stop, with the result that the products can easily be gripped, for example, by a three-finger gripper, in each case one finger of the gripper ending up on the two outer sides of the product and one finger ending up between the overfold region and the region located opposite the overfold region.
During the conveying process preceding the pivoting movement, the products may be transported both in imbricated formation and without overlapping one another. In order to implement the method according to the invention, all that is necessary is for individual products or product groups to follow sequentially one after the other.
Once they have been raised into an at least essentially vertically oriented position, the products may each be gripped individually by grippers, in particular at an upwardly oriented edge, and fed for further processing. It is possible here for the conveying direction of the corresponding gripper section to run essentially perpendicularly to the direction in which the conveying process is oriented immediately prior to the raising operation.
Once the products have been raised into an at least essentially vertically oriented position, however, it is also possible for the products to be pivoted downward assisted by gravitational force, it being possible for this pivoting operation to take place about the same pivot axis as the preceding raising operation. The downward pivoting operation assisted by gravitational force takes place here, in particular, through an angle range of between 90xc2x0 and 180xc2x0. Following the downward pivoting operation, the products may be deposited on a further conveying means or a product stack.
Particularly cost-effective functioning of the method according to the invention is achieved when, during the pivoting movement taking place counter to gravitational force and/or during the pivoting movements assisted by gravitational force, the products are processed, in particular opened, stapled, addressed, cut or the like. In this case, the pivoting movement is not just utilized for lifting off the products from the conveying means; at the same time, it is also possible for processing to take place during the pivoting movement, time being saved in this way.
If folded products are opened during the pivoting movement, it is advantageous if the fold region of the products ends up in the radially inward direction in relation to the pivoting movement. In a particular variant of the method according to the invention, it is then possible, during the pivoting movement, for already open products to have further products inserted into them.
Following the pivoting movement according to the invention, the productsxe2x80x94as has already been mentionedxe2x80x94may be deposited, for example, on a further conveying means. In this case, the conveying direction of this further conveying means may run essentially perpendicularly, or else also parallel, to the direction in which the conveying process was oriented immediately prior to the raising operation. The conveying direction of the products may thus be changed, for example, by 0xc2x0, 90xc2x0, 180xc2x0 or 270xc2x0 by means of the method according to the invention. The further conveying means may be designed, for example, as a gripper section, as a pocket conveyor, as a saddle conveyor, as a combined pocket and saddle conveyor or else also as a conveying belt.
Further preferred embodiments of the method according to the invention are described in the subclaims.